Apparatus for dosing a pharmaceutical product into capsules

ABSTRACT

A machine for dosing a pharmaceutical product into capsules, in which a dosing unit doses a pre-determined quantity of the product into empty capsules by means of dosers and test apparatus operable to test the quantity of the product dosed by the dosers on a sample of the capsules; the testing apparatus including a first and a second weighing unit to weigh, respectively, a capsule before the dosing unit and after the dosing unit; the machine including monitoring means operable, for each capsule of the sample, to evaluate the difference between the weight detected, respectively, by the first and second weighing units to determine the quantity of dosed product.

BACKGROUND OF THE INVENTION

The present invention relates to a method for metering or dosing apharmaceutical product into capsules. The present invention also relatesto a machine for performing the above method.

Metering or dosing of pharmaceutical products, generally as powders,into capsules is obtained using machines in which a metering unit fillsthe empty capsules with a pre-determined quantity of product. Thereaftera testing unit checks a sample of full capsules to determinestatistically if the quantity of product within the capsules lies withinan acceptable range. The measurement of the quantity of product meteredinto the capsules is generally an indirect type of measurement and isobtained by evaluating the difference between the weight of a fullcapsule, detected by the testing unit, and the average weight ofcapsules known from the type of capsules employed. This method involvesthe disadvantage of a somewhat imprecise determination of weight, inparticular when the weight of the quantity of product to be metered intothe capsules is of the same order of magnitude as the weight of thecapsules themselves. In fact, the tolerances of the weight of productand of the capsule can compensate one another with the result that anevaluation of the weight of the product is obtained which issignificantly less or greater than the real value.

In other types of machines, the uncertainty in the average weight ofempty capsules is eliminated by using a method in which the testing unitweighs a full capsule and subsequently pierces each weighed capsule toevacuate the product from the capsule itself by suction. Finally, theemptied capsule is weighed and the difference between the weight of thecapsule full and the weight of the capsule after having been emptied isevaluated. However, even this method involves the disadvantage ofinexact weighing of the pharmaceutical product both because not all ofthe product is always emptied from the capsule and because the measuredweight of the empty capsule is defective by the slivers of capsuleremoved upon piercing.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a method of metering apharmaceutical product into capsules.

According to the present invention there is provided a method of dosinga pharmaceutical product into capsules, comprising a dosing step inwhich a pre-determined quantity of said product is dosed into emptycapsules by dosers, and a testing step in which the quantity of saidproduct dosed into the said capsules during said step is checked, saidtesting step being performed on a sample of said capsules; characterisedin that said testing step comprises, in turn, a first step in whichcapsules of said sample are weighed before filling by means of a firstweighing unit; a second step in which the capsules of said sample areweighed after having been filled, by means of the second weighing unit,and finally, a third step in which, for each capsule of said sample ofcapsules, the difference between the associated weight, respectively,given by said first and second weighing unit is evaluated to determinethe quantity of product in the capsule.

A second object of the present invention is to provide machine forperforming the said method.

According to the present invention there is provided a machine fordosing a pharmaceutical product into capsules, comprising a dosing unitoperable to dose a pre-determined quantity of said product into emptycapsules by means of dosers, and testing apparatus operable to test thequantity of said product introduced by said dosers, said testing beingperformed on a sample of said capsules; characterised by the fact thatsaid testing apparatus includes a first weighing unit in which saidcapsules of the said sample are weighed before dosing; a second weighingunit in which the capsules of said sample are weighed after said dosing;and finally, a third step (SIC) in which, for each capsule of saidsample of capsules the difference between the weights detectedrespectively, by said first and second weighing unit is evaluated todetermine the quantity of product in the capsule.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described with reference to the attacheddrawings which illustrate a non-limitative embodiment thereof, in which:

FIG. 1 is a functional block diagram of a preferred embodiment of amachine for dosing a pharmaceutical product into capsules according tothe present invention;

FIG. 2 is a plan view of a detail of FIG. 1;

FIG. 3 is a section, on an enlarged scale, taken on the line III--III ofFIG. 2;

FIG. 4 is a section, on an enlarged scale, taken on the line IV--IV ofFIG. 2;

FIG. 5 is a section taken on the line V--V of FIG. 4; and

FIG. 6 is a side view of a detail of FIG. 2.

DETAILED DESCRIPTION OF TEE INVENTION

With reference to FIG. 1, the reference numeral 1 schematicallyindicates a machine for metering a pharmaceutical product into capsules2 of hard gelatin, each formed (FIGS. 3 and 4) by a base 3 and a cover 4adapted to contain within it a pre-determined quantity of apharmaceutical product. The machine i includes a dosing unit 5 and afeeder unit 6. The unit 6 feeds the unit 5 with empty capsules 2, andthe unit 5 delivers a dosed quantity of pharmaceutical product into eachempty capsule 2 to supply a packaging machine (not illustrated) withfull capsules 2. The machine 1 further includes testing apparatus 7comprising a first testing unit 8 and a second testing unit 9 which canco-operate with one another to test if a sample of capsules 2 containquantities of dosed product lying within a range of acceptability.Finally, the machine 1 includes an electronic central control andprocessing unit 10 operable to manage the units 5, 6, 8 and 9.Hereinafter pneumatic means for suction and blowing will be described;these means only schematically illustrated since they are of knowntypes.

With reference to FIG. 2, the unit 6 is operable to orientate and orderempty capsules 2 disposed loose in a feed hopper (not illustrated), toform an ordered row 11 of capsules 2 to be conveyed towards the unit 5.The unit 6 includes a drum 12, rotating in a clockwise sense about avertical access 13, provided along its entire lateral surface withcylindrical cavities 14 spaced with a constant pitch and disposed withtheir axes parallel to the axis 13. Each cavity 14 receives a capsule 2of the row 11 along an arc A travelled by the capsules 2 in a clockwisesense from a first end to a second end thereof. In particular, at thefirst end the capsules 2 are released into the cavities 14 by a member(not illustrated and of known type) rotating together with the drum 12,and at the second end the capsules are removed by the same said memberto be conveyed towards the unit 5. To retain each capsule 2 of the row11 in the associated cavity 14 along the arc A, the unit 6 has apneumatic holder device 15.

With reference to FIG. 3, the device 15 comprises a plate 16 mountedfixedly on a support bed 17 and disposed with a lower face in contactwith the drum 12. On this face the plate 16 has a groove 18, closed bythe drum 12 and extending along a circular arc concentric with the arc Aand of the same angular extent. The device 15 further includes aplurality of channels 19, each of which extends within the drum 12between a corresponding cavity 14 and the groove 18. In use, adepression is maintained constantly in the groove 18 by suction means39a so as to maintain a depression in the channels 19 and, consequently,to retain the capsules 2 in the associated cavities 14.

With reference to FIG. 2, along the arc A the unit 6 has a loadingstation 20 at which, in use, some of the capsules 2 of the row 11 areselectively transferred from the unit 6 to unit 8 and define the sampleof capsules 2. The unit 6 also has a discharge station 21 at which thecapsules 2 of the sample of capsules 2 transferred from the unit 8 tothe unit 6. In particular, the station 21 is disposed along the arc Adownstream of the station 20 in the direction of rotation of the drum 12and spaced from the station 20 by a whole number of steps. To release acapsule 2 from the associated cavity 14 the unit 6 includes a releasedevice 22 (FIG. 3) operable to cancel the vacuum in the channel 19 inthe cavity 14 at the station 20. The device 22 includes a small tube 23connected to blower means 39b via a solenoid valve EV1 controlled by thecentral control unit 10. The small tube 23 has a free end disposedwithin the groove 18 at the station 20. The free end of the small tube23 faces the drum 12 so that for each cavity 14 in transit at thestation 20 the associated channel 19 is in communication with the smalltube 23 itself. Upon passage past the station 20 of the capsule 2 to betransferred to the unit 8 the device 22 blows air into the associatedchannel 19 to nullify the vacuum by which the capsule is retained in theassociated cavity 14.

With reference to FIG. 2, the first weighing unit 8 comprises ameasurement station 24 at which the capsules 2 are weighed; a firsttransfer device 25 operable to convey the capsules 2 from the station 20to the station 24; and a second transfer device 26 operable to conveythe capsules 2 from the station 24 to the station 21. The device 25includes a pick-off member 71 and a first conveyor member 28 disposedsequentially between the station 20 and the station 24. The member 71 isoperable to take the capsules 2 from the row 11 to feed the member 28 ofa first intermediate station 29 with these capsules 2. The member 28 isoperable to transfer the capsules 2 from the station 29 to the station24 along a rectilinear path 30.

With reference to FIG. 3, the member 71 includes a shaft 81 mountedparallel to the axis 13 on the support bed 17, and a toothed wheel 82rotatably mounted on the shaft 81 by means of a pair of ball bearings 83and operable to receive drive from a drive device 34 (FIG. 2) of knowntype controlled by the central control unit 10. The member 71 furtherincludes an annular body 84 which is mounted coaxially of and fixed tothe wheel 82 by screws 85 only one of which is illustrated in FIG. 3.The body 84 has an arm 86 extending radially outwardly from the body 84and having at its free end a cylindrical holding cavity 87 disposed withits axis parallel to the shaft 81 and able to receive a capsule 2.

With reference to FIG. 2, under the action of the device 34, the arm 86can turn in an anti-clockwise sense, and its free end describes a circleB which is tangential to the arc A at the station 20, and to therectilinear path 30 at the station 29. The drum 12 and the arm 86 turnin opposite senses with respect to one another and in phase with oneanother in such a way that the cavity 87 and a cavity 14 simultaneouslytransit past the station 20. At each passage of the cavity 87 past thestation 20 the cavity 87 and a cavity 14 reach a position facing oneanother to allow, in use, the capsule 2 carried by the cavity 14 to betaken off by the member 71 to be transferred to the station 29. To takeoff and retain the capsule 2 in the cavity 87 during rotation from thestation 20 to the station 29 the member 71 is provided with a pneumaticholder system 89. The system 89 comprises a suction circuit 90, which inturn comprises an annular chamber 91 defined by the internal peripheryof the body 84 and the external periphery of a cylindrical body 92,fixedly mounted on the shaft 81 and disposed coaxially within the body84. The chamber 91 is, moreover, closed at its axial end by a pair ofannular seals 93. The chamber 91 is in communication with the cavity 87via a duct 94 extending longitudinally within the arm 86. The circuit 90further includes a channel 95 which can connect the chamber 91 tosuction means 39c via a solenoid valve EV6 controlled by the centralcontrol unit 10. The channel 95 extends from the chamber 91 for a firstsection 96 radially through the body 92 as far as the shaft 81 and for asecond section 97 axially within the shaft 81 itself. Under the actionof means 39c the chamber 91 is able to maintain a depression in the duct94 in any position of the arm 86 between the station 20 and the station29. The member 28 includes a pneumatic linear actuator 58, of knowntype, and a holding system 59 for the capsules 2.

With reference to FIG. 6, the system 59 includes a holder body 60fixedly mounted at the free end of a movable arm 61 of the actuator 58and provided with a cylindrical seat 62 which can receive a capsule 2.The system 59 further includes suction means 39d and a channel which canconnect the means 39d with the bottom of the seat 62 through a solenoidvalve EV4 controlled by the central control unit 10. The system 59 is,in use, activated when the body 60 is disposed at the station 29 to sucka capsule 2 from the cavity 38 in the seat 62. The system 59 holds thecapsules 2 in the seat 62 along the path 30 to the station 24. Station24 includes a weighing balance 65 of known type which is provided with avertical rod 66 having at its free end a cylindrical seat 67 forreceiving a capsule 2 released from the body 60. In particular, when thebody 60 reaches the station 24, the seat 62 is facing and above the seat67 and the solenoid valve EV4 is controlled by disconnecting it frommeans 39d and connecting it with blower means 39e in such a way as tostop the suction and create a low pressure inflation to allow thecapsule 2 to pass from the seat 62 to the seat 67. After having weighedthe capsule 2 the weighing balance 65 sends the associated data to thecentral control unit 10 and the capsule 2 is withdrawn by the device 26.The device 26 includes a second conveyer member 70 and an introductionmember 27 disposed sequentially from the station 24 to the station 21.In detail, the member 70 can remove and convey capsules 2 along arectilinear path 72 from the station 24 to a second intermediate station73. The member 27 is operable to remove and convey capsules 2 from thestation 73 to the station 21 at which the capsules 2 are reintroducedinto the row 11.

Like the member 28, and with reference to FIG. 2, the member 70 includesa linear pneumatic actuator 74 of known type and a holder system 75 forcapsules 2. The system 75 includes a holder body 76 similar to the body60. The body 76 is fixedly mounted at the free end of the movable arm(not illustrated because it is similar to the movable arm 61 alreadydescribed) of the actuator 74 and is provided with a cylindrical seat(like the seat 62) in which a capsule 2 can be received. The system 75further includes suction means 39f and a channel for connecting themeans 39f with the bottom of the said seat via a solenoid valve EV5controlled by the central control unit 10. The system 75 is, in use,activated when the holder body 76 is at the station 24 to suck a capsule2 upwardly from the seat 67 of the weighing balance 65. The system 75maintains the capsules 2 in the said seat along the path 72 to thestation 73, at which the solenoid valve EV5 is controlled to disconnectitself from means 39f and to connect itself to blower means 39g so as tostop the suction and create a low pressure blowing to allow the capsule2 to be transferred from the member 70 to the member 27.

With reference to FIG. 4 the member 27, like the member 71, includes ashaft 31 mounted parallel to the axis 13 on the support bed 17 and atoothed wheel 32 mounted rotatably on the shaft 31 by a pair of ballbearings 33 and can be driven by the device 34. The member 27, furtherincludes an annular body 35 which is mounted coaxially and fixedly onthe wheel 32 by screws 36 only one of which is illustrated in FIG. 4.The body 35 has an arm 37 extending radially outwardly from the body 35and having at its free end a cylindrical holding cavity 38 disposed withits axis parallel to the shaft 31 so as to be able to receive a capsule2.

With reference to FIG. 2, under the action of the device 34, the arm 37can turn in an anti-clockwise sense and its free end can describe acircle C tangential to the rectilinear path 72 at the intermediatestation 73 and to the arc A at station 21. To remove a capsule 2 andretain it in the cavity 38 during rotation from the intermediate station73 to the discharge station 21, the member 27 is provided with a holdingand release system 41 of pneumatic type illustrated in FIGS. 4 and 5.The system 41 comprises a suction circuit 42 and a blowing circuit 43.Circuit 42 includes an annular chamber 44 defined by the inner peripheryof the body 35 and the outer periphery of a cylindrical body 45 fixedlymounted over the shaft 31 and disposed coaxially within the body 35. Thechamber 44 is, moreover, closed at its axial ends by a pair of annularseals 46. Chamber 44 is connected to the cavity 38 by a duct 47extending longitudinally within the arm 37. The circuit 42 furtherincludes a channel 48 which can connect the chamber 44 to suction means39h via a solenoid valve EV2. The channel 48 extends from the chamber 44for a first section 49 radially through the body 45 to the interior ofthe shaft 31 and axially through the shaft 31 for a second section 50.The chamber 44 can maintain a depression in the duct 47 in any angularposition of the arm 37 between the station 73 and of the station 21.Upon passage of the cavity 38 through the station 73 the system 75 ofthe member 70 is disactivated to allow a capsule 2 housed in the body 76to be removed by the member 27 via its holding system 41.

The circuit 43 is operable to create a slight pressure in the duct 47upon passage of the cavity 38 past the station 21 to nullify,substantially instantaneously, the depression in the duct 47 whichretains the capsule 2 in the cavity 38. The circuit 43 includes achannel 51 extending within the shaft 31 to connect a radial passage 56(FIG. 5) formed in the body 45 to the blower means 39i via a solenoidvalve EV3. The circuit 43 further includes a diverter element 52disposed within the passage 56 and able to connect the channel 51 to theduct 47 upon passage of the cavity 38 past the station 21. It is to benoted that the section shown in FIG. 5 is not an exact representation ofthe section defined line V--V of FIG. 4, but a similar section in which,the slot 56 of the body 45 is shown in alignment with the duct 47. It isthus possible to show the operation of the member 27 with greaterclarity.

The element 52 includes a tubular body 53 traversed longitudinally by aduct 54, and a spring 55 mounted under compression between the body 53and the shaft 31 to press the body 53 against the body 35. When, in use,the cavity 38 transits the station 21 the duct 47 is disposed coaxiallyof the duct 54 and in communication with the said blower means 39i whichare actuated to blow air into the duct 47. The drum 12 and the arm 37rotate in opposite senses with respect to one another and in phase withone another in such a way that the cavity 38 and a cavity 14simultaneously transit the station 21. At each passage of the cavity 38through the station 21, the cavity 38 and a cavity 14 are located facingone another to allow a capsule 2 carried by the cavity 38 to be removedfrom the unit 6 and reintroduced into the row 11 following disactivationof the circuit 42 and activation of the circuit 43. Once reintroducedinto the row 11 the capsules 2 are conveyed towards the unit 5 which isoperable, successively, to separate the covers 4 from the bases 3 toopen the empty capsules 2, and to meter or dose a pre-determinedquantity of products into the bases 3 by means of a plurality of dosers5a schematically illustrated in FIG. 1 since they are of known type, andthen to reclose the bases 3 with the associated covers 4. Thethus-filled capsules 2 are conveyed towards the said packaging machineby a conveyer device (not illustrated) with which the unit 5 isprovided. Under the control of the central control unit 10 the conveyerdevice can, moreover, selectively divert capsules 2, previously weighedat the unit 8, towards the unit 9. The unit 9, of known type, isoperable to weigh each capsule 2 of the said sample of capsules 2 and tosend the associated data to the central control unit 10. The centralcontrol unit 10, also of known type, is operable to co-ordinate theunits 5, 6, 8 and 9 with one another and to process data received fromthe units 8 and 9 in a manner which will be described hereinbelow.

In use the unit 5 is supplied with capsules 2 from the row 11 to meteror dose a pre-determined quantity of pharmaceutical product into eachcapsule 2 by a plurality of dosers 5a, and in turn supplies, via theconveyer device (not illustrated) a packaging machine (not illustrated)with full capsules 2. At each passage of the cavity 87 past the loadingstation 20 the release device 22 of the unit 6 and the suction circuit90 of the member 71 are activated to allow the member 71 to withdraw acapsule 2 from the drum 12. Following subsequent rotation of the arm 86in an anti-clockwise sense the capsule 2 arrives at the station 29 inwhich the capsule 2 is released by the member 71 to the member 28 afterthe circuit 90 has been disactivated and the holding system 59activated. Under the thrust of the actuator 58 the capsule 2 istransferred into the station 24, which acts to weigh the capsule 2.After weighing has been completed the station 24 sends the associateddata to the central control unit 10 and the capsule 2 is taken off bythe member 70. Under the thrust of the actuator 74 the capsule 2 istransported from the station 24 to the station 73. At station 73 thecapsule 2 is taken off by the member 27 by actuation of the circuit 42,and transferred to station 21 after anti-clockwise rotation. At station21 the capsule 2 is taken off by unit 6 to be conveyed to unit 5. Themembers 71 and 27 rotate in phase with respect to one another in such away that a capsule 2 is taken off by the member 71 at station 20 andsimultaneously a capsule 2 is taken off by the member 27 at station 73,whilst simultaneously a capsule 2 is released up by the member 71 atstation 29 and a capsule 2 is released by the member 27 at station 21.In particular, at station 21 the capsule 2 is housed within a cavity 14of the drum 12 which has no associated capsule 2 because it has beentaken by the member 71 upon passage through the station 20. At the unit5 the capsule 2 is opened by separating the cover 4 from the base 3, apre-determined quantity of the product is dosed into the base 3 by adoser 5a, and finally the base 3 is closed by the associated cover 4.Following this the capsule 2 is diverted towards the unit 9 via the saidconveyer device.

The unit 9 provides for weighing the capsule 2 and sends the associateddata to the central control unit 10 for processing. In the first placethe central control unit 10 evaluates the weight of the quantity ofdosed product within each capsule 2 of the sample. This value isobtained as the difference between the data coming from the unit 9 andthe data coming from the unit 8. Subsequently, the weight of thequantity of product is compared with a pair of values delimiting thesaid range of acceptability of the capsule 2. If the weight of thequantity of product is outside the said range, the central processingunit 10 activates the unit 9 to reject the capsule 2. If the weight iswithin the range the central unit 10 activates the unit 9 to convey thecapsule 2 towards the packaging machine (not illustrated).

Secondly, the central control unit 10 statistically processes theweights of the quantities of product dosed into the capsules 2 in orderto monitor over time the efficiency of the dosers 5a of the unit 5. Theweights obtained by the data coming from the units 8 and 9 arere-grouped into sets of values, each of which comprises the weights ofcapsules 2 into which the product has been dosed by the same doser 5a.In order to weigh capsules 2 intended, in succession, for differentdosers 5a the angular velocity of the drum 12 and of the takeoff member71 are chosen in such a way that the member 71 successively takescapsules 2 from the row 11 which are each intended for a different doser5a in the same succession. The central control unit 10 is also able tostop the machine 1 when one or more of the dosers 5a repeatedly deliversproduct in quantities outside the pre-determined range.

From what has been described above the advantages achieved by theembodiment of the present invention will be apparent.

In particular, the quantity of product dosed into capsules 2 isdetermined with high precision in that it is evaluated as a differencebetween the weight of the full capsule and the weight of the emptycapsule which is measured with precision by the first weighing unit.Moreover, the statistical processing of the weights of dosed product inthe said sets of values makes it possible to monitor the operation ofthe dosers and the uniformity of the product over time. If, for aspecific set of values, the quantity of dosed product is outside thesaid range, it is evident that a doser has lost its efficiency and it ispossible to stop the machine to operate directly on that doser device.If, all the sets the quantities of product are outside the range ofacceptability it is evident that the pharmaceutical product supplied tothe dosing unit does not have the required density characteristics.

Finally, it is clear that modifications and variations can be introducedto the method and the machine described above, without departing fromthe protective ambit of the present invention.

In particular, in a variant not illustrated, the dosing unit is providedwith an automatic dosing adjustment device. The device is connected tothe central control and processing unit in order selectively andautomatically to operate on those metering devices 5a which have losttheir efficiency.

What is claimed is:
 1. A machine for dosing a pharmaceutical productinto capsules, comprising; a dosing unit operable to dose apre-determined quantity of said product into empty capsules by means ofdosers and a test apparatus operable to test the quantity of saidproduct dosed by said dosers, said testing being performed on a sampleof said capsules, characterised in that said testing apparatus includesa first weighing unit in which said capsules of said sample are weighedbefore said dosing, a second weighing unit in which the capsules of saidsample are weighed after said dosing, and processing and monitoringmeans operable, for each capsule of said sample, to evaluate thedifference between the weight detected, respectively, by said first andsecond weighing units to determine the quantity of dosed product; saidmachine further including a feed unit operable to form an orderedsuccession of said empty capsules and to convey said empty capsulestowards said dosers; said feed unit including a loading station at whichsaid empty capsule is transferred to said first weighing unit, and adischarge station at which said empty capsule is received from saidfirst weighing unit; said feed unit including a rotating drum havingcylindrical cavities provided around the whole of the lateral surface ofsaid rotating drum, spaced with constant pitch and able to receive saidcapsules of said succession along an arc of the circumference; saidloading and discharge stations being disposed along said arc.
 2. Amachine according to claim 1, characterised in that said feed unitincludes holder means for holding said capsules of the succession inassociated cylindrical cavities along said arc, said feeding unitfurther including release means for releasing a capsule to said firstweighing unit when said capsule is in said loading station.
 3. A machineaccording to claim 1, characterised in that said first weighing unitincludes a first transfer device, a second transfer device, and ameasuring station including a weighing balance; the first device beingoperable to transfer each capsule of said sample from said loadingstation towards said measuring station where said capsule is weighed,and said second device being operable to transfer said capsule from saidmeasuring station towards said discharge station for reintroducing saidcapsule into said succession of capsules.
 4. A machine according toclaim 3, characterised in that said first transfer device includes atake-off member operable to take one said capsule from said successionof capsules at said loading station, and a first conveyor membersupplied with said capsule at a first intermediate station to move saidcapsule from said intermediate station to said measurement station.
 5. Amachine according to claim 4, characterised in that said take-off memberincludes a first driven arm rotatable about a support shaft in anopposite sense with respect to said drum, said first driven arm havingat the free end of said first driven arm a first holding cavity forhousing a capsule, the free end of said first driven arm describing afirst circle tangential to said arc at said loading station, in whichsaid first holding cavity and one of the cylindrical cavities face oneanother to allow a capsule carried by said cylindrical cavity to betaken off by said take-off member and transferred to said firstintermediate station.
 6. A machine according to claim 5, characterisedin that said take-off member further includes holding means operable togrip a capsule when said first holding cavity passes said loadingstation, to retain said capsule in passing from said loading station tosaid intermediate station, and finally to release said capsule at saidintermediate station.
 7. A machine according to claim 4, characterisedin that said first conveyor member comprises a first linear actuator anda first holding system for capsules, said first holding system includinga first holding body fixedly mounted at the free end of a first movablearm of said first actuator and provided with a cylindrical seat forhousing a capsule.
 8. A machine according to claim 4, characterised inthat said second transfer device includes a second conveyor member andan introduction member, said second conveyor member being operable tomove one of said capsules from said measurement station to a secondintermediate station to supply said introduction member which isoperable to introduce said capsule into said succession at saiddischarge station.
 9. A machine according to claim 8, characterised inthat said second conveyor member includes a second linear actuator and asecond holding system for the capsules, and wherein said second holdingsystem includes a second holding body fixedly mounted at the free end ofa second movable arm of said second actuator and provided with acylindrical seat for receiving a capsule.
 10. A machine according toclaim 8, characterised in that said introduction member includes asecond driven arm rotatable about a support shaft in an opposite sensefrom said drum, said second arm having at its free end a second holdingcavity for receiving a capsule, the free end of said second armdescribing a second circle tangential to said arc at said dischargestation, in which said second cavity and one of the cylindrical cavitiesare facing one another to allow a capsule carried by said second holdingcavity to be taken off by said drum.
 11. A machine according to claim10, characterised in that said introduction member further includesholding and release means operable to grip a capsule when said secondholding cavity passes the second intermediate station to retain andcarry said capsule from said second intermediate station to saiddischarge station, and finally to release said capsule at said dischargestation.
 12. A machine for testing the amount of a pharmaceuticalproduct being dosed into capsules by a dosing unit, comprising:a firstweighing unit for weighing a selected capsule before the selectedcapsule is dosed by the dosing unit; a second weighing unit for weighingthe selected capsule after the selected capsule is dosed by the dosingunit; processing means to evaluate the difference between the weightsmeasured by the first and second weighing units to determine the amountof dosed product in the selected capsule; and a feed unit for forming anordered succession of empty capsules to convey the empty capsulestowards the dosing unit, the feed unit includinga rotating drum havingcylindrical cavities on the lateral surface of the rotating drum, thecylindrical cavities being spaced apart from each other and adapted toreceive the empty capsules; a loading station at which the selectedcapsule is transferred from the rotating drum to the first weighingunit; and a discharge station at which the selected capsule istransferred from the first weighing unit into the rotating drum afterthe selected capsule is weighed by the first weighing unit.
 13. Themachine according to claim 12 wherein the feed unit furthercomprises:holder means for holding the empty capsules in the cylindricalcavities; and release means for releasing the selected capsule of theempty capsules to the first weighing unit when the selected capsule ispositioned at the loading station.
 14. The machine according to claim 12wherein the first weighing unit comprises:a measuring station includinga weighing balance; a first transfer device for transferring theselected capsule from the loading station towards the measuring stationwherein the selected capsule is weighed by the weighing balance; and asecond transfer device for transferring the selected capsule from themeasuring station towards the discharge station for reintroducing theselected capsule into the succession of the empty capsules.
 15. Themachine according to claim 14 wherein the first transfer devicecomprises:a take-off member positioned to receive the selected capsuleat the loading station; and a conveyor member positioned to receive theselected capsule from the take-off member, the conveyor member formoving the received selected capsule to the measurement station.
 16. Themachine according to claim 15 wherein the take-off member comprises:adriven arm having a free end and being rotatable about a support shaft;and a holding cavity positioned at the free end for receiving theselected capsule, the free end describing a circle tangential to thelateral surface of the rotating drum at the loading station, wherein theholding cavity and the cylindrical cavity holding the selected capsuleface each other to allow the selected capsule to be transferred from thecylindrical cavity to the holding cavity.
 17. The machine according toclaim 16 wherein the take-off member further comprises holding means forretaining the selected capsule when the holding cavity passes theloading station and receives the selected capsule.
 18. The machineaccording to claim 15 wherein the conveyor member comprises:a linearactuator including a moveable arm slidably mounted therein; and aholding body mounted at the free end of the movable arm, wherein theselected capsule is received in the holding body from the take-offmember, and the linear actuator moves the holding body containing theselected capsule towards the measuring station.